Process of etherifying cellulose



Patented Aug. 18, 1931 UNITED STATES PATENT OFFICE FREDERICK C. HAHN, OF WILMINGTON, DELAWARE, ASSIGNOR TO E. I. DU PON'I DE NEMOURS & COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELA- WARE PROCESS OF ETHERIFYING CELLULOSE No Drawing.

This invention relates to a process of etherifying cellulose, and more particularly to such a process wherein an intimate mixture of the ingredients is secured without grinding the cellulose with any alkali.

It is an object of this invention to improve upon similar processes for etherifying cellulose, by avoiding a grinding of the cellulose with alkali, as such an operation has 0 been found to be injurious to the cellulose if the grinding is at all severe. It is a further object toprepare a cellulose ether by intimately mixing the ingredients so that a reaction will take place that will result in a product of superior quality and of a suitable film forming property. It is a still further object to so conduct the process as to avoid incorporation of soda solutions in the cellulose and thereby avoid the entry of excess water, which would have the effect of interfering with a proper alkylation. Further objects of the invention will be apparent as the following description proceeds.

The invention may be conveniently carried out as follows: I first grind the cellulose to a suitable degree of fineness. There is also repared a slurry of caustic soda in benzol benzene), the caustic being suitably :50 subdivided. Into this slurry I introduce the ground cellulose and the ingredients are thoroughly mixed to provide an intimate admixture and then placed in the autoclave, which may be charged to its full operating capacity, and the process is thereafter conducted in the manner known in the art by introducing the etherifying compound, such as methyl chloride or ethyl chloride, in

proper proportion to provide the necessarycomponent for the formation of the cellulose ether. The various details of operation need not be further described, as they may be found in procedures of the prior art, such as Patent 1,501,207

In this manner there is avoided any grinding of cellulose with alkali whereby any impairment of the ultimate quality of the cellulose ether is effected and the film forming quality of the product is suitably main- 59 tained. The procedure also avoids other dif- Application filed May 14, 1928. Serial No. 277,795.

ficulties of prior practices, such as defective etherification or the employment of too large linter particles. It will thus be seen that I have achieved the objects of the invention in a satisfactory manner.

As many apparently widely different embodiments of this invention may be made without departing from the spirit thereof, it is to be understood that I do not limit myself to the foregoing examples or descriptions except as indicated in the following claims.

I claim:

1. In a. process of etherifying cellulose to obtain a cellulose ether wherein the cellulose is treated with an alkali and an alkyl compound, the procedure comprising completing the grinding of the cellulose apart from the alkali, then adding it to a slurry of alkali in an inert liquid and intimately mixing it therewith, and thereupon etherifying it.

2. In a process of etherifying cellulose to obtain a cellulose ether wherein the cellulose is treated with an alkali and an alkyl compound, the procedure comprising first grinding the cellulose, then adding it without further grinding to a slurry of alkali in a non-etherifiable liquid and intimately mixing it therewith, and thereupon etherifying.

3. In a process of etherifying cellulose to obtain a cellulose ether wherein the cellulose is treated with an alkali and an alkyl compound, the procedure comprising first grinding the cellulose, then adding it without further grinding to a slurry of alkali in benzol and intimately mixing it therewith, and thereupon etherifying.

4. In the process of etherifying cellulose wherein a cellulose is treated with an alkali and thereafter with an alkyl compound, the method which comprises grinding the alkali to a slurry in an inert liquid, separately grinding the cellulose and thereafter intimately mixing the cellulose with the alkali slurry.

In testimony whereof, I afiix my signature.

FREDERICK C. HAHN. 

